Valve for single-chamber air-pressure brakes



NOV. 27, 192 1,475,432

W. HILDEBRAND VALVE FOR SINGLE CHAMBER AIR PRESSURE BRAKES Filed April10 1923 Patented Nov. 27, 1923.

entree stares iavaisz WILHELM HILDEBBAND, or BERLIN, ensiannv, nssleno'aTo HAIiTDEL-MAAT- SCHAPIPIJ' H. ALBERT DE BABY a 00., or AMSTERDAM,NETHERLANDS.

VALVE FOR SINGLE-CHAMBER AIR-PRESSURE BftfsKEs.

Application filed April 10, 1322. Serial No. 631,141,

To all whom it may concern Be it known that I, VVILHELM HILDE' BRAND, acitizen of the German Republic,

residing at 9-17, Neue Bahnhofstrasse, Lichtenberg O. 112, Berlin,Germany, have invented certain new and useful Improvements in Valves forSingle-Chamber Air- Pressure Brakes, of which the following is aspecification. c 1

This invention relates to valves for single chamber air pressure brakes,its object being to provide in addition to the graduated increase of thebraking action means for obtaining a graduated reduction thereof, thatis to say, a step by step release of the brake, while avoiding thedifficulties arising from the division of the auxiliary air reservoirinto two chambers by a braking piston of large diameter and frictionalresistance as described in the prior United States patent specificationNo. 1325, 177.

According to this invention a regulating container divided into twochambers of variable capacity is inserted into the connection betweenthetrain pipe and the auxiliary air reservoir, and in the said. containeris provided an easily working piston mounted on a common piston rod withasmaller counter piston working in a guide tube or recess. The chamberin which the counter piston is located is connected with the chamber ofthe brake filling valve, and the other chamber of the regulatingcontainer is in direct communication with the auxiliary reservoir, andin communication through the sald filhng valve with the train pipe.

In order that the saidinvention may be clearly understood and readilycarried into effect, the same will now be described more fully withreference to the accompanying drawings, in which Figure 1 showsdiagrammatically the ap paratus in the release position.

Figure 2 shows the sameapparatus in the position assumed when applyingthe brake.

The reference letter 6 indicates the train auxiliary reservoir a whenthe valve 2' is in theposition shown in Figure 2 the valve 39 in thevalve chamber (Z then closing the connection between the brake cylinder0' and the open air through the recess a in the til) valve 2', the pipem, and the recess 76 in the ferential piston comprising a larger pistong and a small counter piston h, this chamher 8 being constantly incommunication with the interior of the casing (Z of the filling valve29. In the normal position shown in Figure 1 pressure in the chambers sand t is equalized through a filling grooveadjacent to the piston g.

When 'the pressure in the train pipe 6 is reduced to applythe brake, thepistons of the valves 71 and 39 will pass into the posi-v tions shown inFigure 2, when air from the reservoir a acts on the piston in the brakecylinder 0, the connection between the pipes r and g is interrupted andthe reduction of pressure in the reservoir a and chamber t allows thepiston g to move to the left beyond its filling groove w, the counterpiston h of course partaking in this movement. If

the pressure in the train pipe e has only been slightly reduced so thatin these movements the pressure in the auxiliary reservoir 0 falls belowthat in the train pipe, the distributing slide valve 71 will be forcedback into the release position, but the connection between the brakecylinderc and the open air is not reestablished because the fillingslide valve p remains in the brake on position owing'to the pressure inthe chamber 8 being maintained by the movement of the counter piston hat a higher level than that in the chamber t. By a further reduction ofthe pressure in the train pipe the slide valve 2' can again be broughtinto the brake on position to place the auxiliary reservoir incommunication with the brake cylinder.

For the purpose of obtaining a graduated release of the brakes, thepressure in the train pipe is so much increased that it somewhat exceedsthe pressure in the auxiliary rese voir. The dist hating valve 2' andfillin valve then pass into the release pesition, so that the air beginsto escape from the brake cylinder, but at the same time the chamber 5'of the regulating container is connected with the train pipe 6 throughthe pipe 9, recess Z and pipe 1", hence the pres- E L1I'6 in the chamberat increases and forces the difierential piston g h to the right, causapressure in the chamber .9 which, owing to the presence of the counterpiston it errceeds the train pipe pressure and the valve 7) is thusforced downward, whereby the re leasing process is stopped and therelease cut-off position induced. In order to effect the completerelease oi the brake the full poise of pressure at both sides or thepiston g.

What I claim and desire to secure by Letters Patent of the United Statesis 1.1n a single chamber compressed air brake, a train pipe, anauxiliary air reservoir, a brake cylinder, a connection between saidreservoir and said cylinder, a connection between said cylinder and theatmosphere, a distributing valve controlling both said connections, aregulating container comprising two chambers of variable capac tweensaid cylinder and the atmosphere,

said piston being; adapted to control the movements of said fillingvalve. a

2. Distributing means'for sin le chambercompressed airbrakescharacterized by the facts that controlling device is provided forapplying and releasing the brake and another controlling device isprovided for filling the brake, and thatfor the purpose of permitting agraduated release between the auxiliary air reservoir and the fillingcontrol device there is provid container having a diiierential piston,in which container the chamberat one side of the larger piston isconnected with the said auxiliary air reservoir and with the traipipe,while this latter'connection is intere rupted by the filling controlvalve upon application of the brake, while the chamber at the other sideof the separatingpiston of the regulating container situated towards thecounter piston is connected with the distributin slide valve chamber ofthe filling control valve.

wiLnELM HILDEBRAN Q red a regulating 1

